This application is a 371 of PCT/EP98/07283 filed Nov. 13, 1998.
1. Field of the Invention
The invention relates to a method and an apparatus for signalling local traffic disturbances, and in particular to a method and an apparatus for recognising and indicating accidents and an increased traffic volume as well as tailbacks caused thereby.
2. Description of the Related Art
In order to avoid tailbacks and accidents in the event of increased traffic volume, conventional traffic control systems have already been fixedly installed along road sections with particularly much traffic such as, for example, highly frequented highways, etc. Such conventional, fixedly installed traffic control systems possess a multiplicity of detection means detecting, for example, traffic density, the velocity of the flow of vehicles, environmental conditions (temperature, fog) etc., and control vehicle traffic through the respective detection signals along the predetermined section with the aid of indicator panels, so that a tailback or accidents are avoided where possible.
A drawback in the like conventional traffic control systems is the fixed installation along a predetermined route section which results in extraordinarily high costs for their acquisition. Moreover a like fixedly installed traffic control system only possesses low flexibility as it regulates, or controls, traffic only in relatively short section.
In order to enhance flexibility, U.S. Pat. No. 4,706,086 proposes a communication system between a multiplicity of automotive vehicles wherein signals and information corresponding to the respective running conditions of the automobile are transmitted via a transmitting/receiving device by means of electromagnetic radio waves.
From document U.S. Pat. No. 5,428,544 there are moreover known a device and a method for signalling local traffic disturbances, wherein the vehicle data or conditions, respectively, of the automobile such as, for example, speed, route and direction are mutually transmitted via communication means. Transmission of the respective data to another automotive vehicle is achieved in an indirect manner through a passing automobile travelling in the opposite direction. In addition, this conventional traffic information system requires a navigation module, a map module, and own-position determination apparatus for identifying one""s own position. The like conventional communication systems do, however, present the drawback of definitely requiring a multiplicity of extraordinarily costly elements, such as, for example, a map memory, a navigation module and a positioning module for recognising one""s own position.
From EP-A-0 715 286, a method for signalling local traffic disturbances in accordance with the preamble of claim 1, and an apparatus for signalling local traffic disturbances in accordance with the preamble of claim 10 are known.
The invention is therefore based on the object of furnishing a method and an apparatus for signalling local traffic disturbances which may be furnished at relatively low cost, possess a high degree of flexibility, and are independent of fixedly installed detection means.
In accordance with the invention, this object is attained through the measures indicated in claim 1 with respect to the method, and through the measures indicated in claim 11 with respect to the apparatus.
Further advantageous embodiments of the present invention are the subject matters of the dependent claims.
To be more precise, a maximum group of vehicles to be considered is determined in accordance with a predetermined minimum signal level of an electromagnetic radio signal emitted by a respective multiplicity of vehicles. The individual vehicle data transmitted by the radio signal and representing the respective moving conditions of the vehicles located within the reception range are repeatedly evaluated and memorised. With the aid of the memorised vehicle data, a group of reference vehicles relevant for a respective vehicle to be examined within the maximum group of vehicles to be examined is determined by evaluating the individual vehicle data. Subsequently the group behavior within the relevant group is determined by means of the individual vehicle data. This group behavior is signalled in the reference vehicle, so that a driver is informed in good time about possible changes or hazards within his relevant group of vehicles. Accidents and tailbacks may thus be recognised in time or avoided.
Determination of the relevant group of vehicles is preferably effected with the aid of a method for fractal-darwinian object generation, wherein an order or sequence, respectively, within a group of vehicles is continuously generated by considering the respective vehicle data and subsequent weighting of an eventual position likelihood. Hereby an accurate positioning or sequence of respective vehicles within a group may be determined already through a minimum number of vehicle data without employing costly positioning systems.
A respective maximum group to be examined may, in particular, result from a maximum reception range of a reception device. It may, however, also be determined through a maximum memory capacity.
As vehicle data, preferably an identification code for identifying a respective vehicle, a velocity value for indicating a current speed of the vehicle, and a distance parameter are used. The distance parameter representing a distance between the reference vehicle and the respective vehicles from among the maximum group to be examined may, for example, be deducted from the reception field strength of the respective emitted radio signal.
As further vehicle data, for example a deceleration/acceleration value for indicating a current deceleration/acceleration of the respective vehicle, a steering angle for indicating a current steering angle of the respective vehicle, a direction value for indicating a current absolute direction, a position value for indicating a current absolute position of the respective vehicle, and a brake signal value for indicating a current use of a brake device of the respective vehicle are conceivable. Moreover it is also possible to pass on a group behavior value as vehicle data which represents the current group behavior of a relevant group associated with the reference vehicle.
The information signalled in the reference vehicle may be made both visible and audible through indicator means. It may, however, also directly result in a control of the braking behavior of the reference vehicle or influence engine control, whereby, for example, automatic emergency braking may be performed.
In particular where a predetermined combination of individual vehicle data is present, i.e. of moving conditions of a respective vehicle, an emergency signal having a higher priority than the individual vehicle data signals may be generated. Thus it is possible, for example in the event of imminent danger, to pass this condition on as rapidly as possible to groups of vehicles located further behind, resulting in particularly rapid dissemination of information. In order to avoid a multiplicity of emergency signals, such an emergency signal is passed on in an amplified condition (repeater function) only if its reception field strength drops below a predetermined threshold.